43 research outputs found
A General Unfolding Speech Enhancement Method Motivated by Taylor's Theorem
While deep neural networks have facilitated significant advancements in the
field of speech enhancement, most existing methods are developed following
either empirical or relatively blind criteria, lacking adequate guidelines in
pipeline design. Inspired by Taylor's theorem, we propose a general unfolding
framework for both single- and multi-channel speech enhancement tasks.
Concretely, we formulate the complex spectrum recovery into the spectral
magnitude mapping in the neighborhood space of the noisy mixture, in which an
unknown sparse term is introduced and applied for phase modification in
advance. Based on that, the mapping function is decomposed into the
superimposition of the 0th-order and high-order polynomials in Taylor's series,
where the former coarsely removes the interference in the magnitude domain and
the latter progressively complements the remaining spectral detail in the
complex spectrum domain. In addition, we study the relation between adjacent
order terms and reveal that each high-order term can be recursively estimated
with its lower-order term, and each high-order term is then proposed to
evaluate using a surrogate function with trainable weights so that the whole
system can be trained in an end-to-end manner. Given that the proposed
framework is devised based on Taylor's theorem, it possesses improved internal
flexibility. Extensive experiments are conducted on WSJ0-SI84, DNS-Challenge,
Voicebank+Demand, spatialized Librispeech, and L3DAS22 multi-channel speech
enhancement challenge datasets. Quantitative results show that the proposed
approach yields competitive performance over existing top-performing approaches
in terms of multiple objective metrics.Comment: Submitted to TASLP, revised version, 17 page
DMF-Net: A decoupling-style multi-band fusion model for full-band speech enhancement
For the difficulty and large computational complexity of modeling more
frequency bands, full-band speech enhancement based on deep neural networks is
still challenging. Previous studies usually adopt compressed full-band speech
features in Bark and ERB scale with relatively low frequency resolution,
leading to degraded performance, especially in the high-frequency region. In
this paper, we propose a decoupling-style multi-band fusion model to perform
full-band speech denoising and dereverberation. Instead of optimizing the
full-band speech by a single network structure, we decompose the full-band
target into multi sub-band speech features and then employ a multi-stage chain
optimization strategy to estimate clean spectrum stage by stage. Specifically,
the low- (0-8 kHz), middle- (8-16 kHz), and high-frequency (16-24 kHz) regions
are mapped by three separate sub-networks and are then fused to obtain the
full-band clean target STFT spectrum. Comprehensive experiments on two public
datasets demonstrate that the proposed method outperforms previous advanced
systems and yields promising performance in terms of speech quality and
intelligibility in real complex scenarios
Alternative splicing in the variable domain of CaMKIIβ affects the level of F-actin association in developing neurons.
The Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) β has an essential function in dendritic spines via binding to and reorganization of the actin cytoskeleton during plasticity events not shared by CaMKIIα isoform. CaMKIIβ and CaMKIIα isoforms have remarkable structural differences within the variable region. Three exons (E1, E3, and E4) are present in CaMKIIβ but not in CaMKIIα gene. Four splice variants of CaMKIIβ isoforms (CaMKIIβ, β\u27, βe and β\u27e) were discovered in embryonic and adult brains. Exons E1 (lacked in βe and β\u27e) and E4 (lacked in β\u27 and β\u27e) are subject to differential alternative splicing. We hypothesized that the sequences encoded by exons E1, E3, and/or E4 are involved in CaMKIIβ-specific bundling to the F-actin cytoskeleton. We tested the colocalization and association of these CaMKIIβ variants within an F-actin-rich structure (microspike) in CaMKIIα free embryonic day 18 (E-18) rat cortical neurons. Our results showed that CaMKIIβ and CaMKIIβ\u27 containing exon E1 displayed an association with F-actin, while CaMKIIβe and CaMKIIβ\u27e lacking E1 did not. Moreover, CaMKIIβ\u27 lacking exon E4 but having E1 showed decreased actin bindingcapacity compared to WT CaMKIIβ. This suggested E1 is required for the association between CaMKIIβ and F-actin, while E4 assists CaMKIIβ to associate with F-actin better. Thus, alternative splicing of CaMKIIβ variants in developing neurons may serve as a developmental switch for actin cytoskeleton-associated isoforms and therefore correlated with dendritic arborization and synapse formation during LTP